Corner key for screen frames and the like



June 27, 1961 M. KESSLER 2,989,788

CORNER KEY FOR SCREEN FRAMES AND THE LIKE Filed March 9, 1959 2 sheets sheet 1 I INVENTOR MIL TO/V KESSL ER I ATTORNEY M. KESSLER CORNER KEY FOR SCREEN FRAMES AND THE LIKE Filed March 9, 1959 June 27, 1961 2 Sheets-Sheet 2 INVENTOR MILTON Ksssz. ER

ATTORNEY United States Patent Oflice 2,989,788 Patented June 27, 1961 2,989,788 CORNER KEY FOR SCREEN FRAMES AND THE LIKE Milton Kessler, 4535 Grove Drive, Youngstown, Ohio Filed Mar. 9, 1959, Ser. No. 797,924 4 Claims. (Cl. 20--56.1)

This invention relates to a corner key for frame members, such as are used for screens and similarly relatively light structures, which frame members are of hollow construction, usually mitred at the corners, and assembled by means of a right-angled key, as shown for example, in U.S. Patent to Borche'rt, No. 1,734,710, issued November 5, 1929. However, in the Borchert patent, the key is made to fit closely into the hollow portion of the frame, and is then soldered or otherwise fastened in place to prevent removal. This requires relatively close tolerances, and also relatively skilled labor in assembly.

It is a major object of the invention to provide a frame assembly of hollow frame members, joined at the corners by means of a right angled key fitting into the hollow portion of the frame members, which can be readily assembled by unskilled help, without the aid of tools or external fastening means, yet which holds firmly and provides a strong, rigid frame assembly. The corner key according to the invention is preferably made of strong rigid plastic material, and is provided near the ends of the key with a special type of fin, which has a locking action, yet which can be readily inserted into place, although thereafter it can be withdrawn only with considerable diflficulty.

The specific nature of the invention, as well as other objects and advantages thereof, will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings, in which:

FIG. 1 is a perspective view, partly cut away, of a screen construction adapted to be used with the present invention;

FIG. 2 is a cross sectional view of a portion of the screen frame taken along line 2--2 of FIG. 4;

FIG. 3 is an exploded view of a corner of the frame, showing the relation of the locking key and the ends of the frame members;

FIG. 4 is a longitudinal sectional view taken on lin 44 of FIG. 2;

FIGS. 5-7 inclusive are transverse sectional views of the holding ends of various modifications of the invention;

FIG. 8 shows still another modification in which the interior of the frame is tubular;

FIG. 9 shows a locking key adapted to fit into the structure of FIG. 8;

FIG. 10 shows a modified form of the invention, partly broken away to show details;

FIGS. 11, 12 and 13 are sectional views taken on lines 11-11, 12-12, and 13-13, respectively, of FIG. 10.

The invention is applied to a screen 2 having frame members 3 provided with a known type of lip 4 for receiving the screen 6 which is locked in by means of a spline 7 in known fashion. The frame 3 is shown as an extruded type of frame, made of either plastic of a light material such as aluminum, but may also be made of folded sheet metal as shown in the above-mentioned Borchert patent.

FIG. 3 shows the manner in which two adjacent frame members are assembled at right angles by means of a right-angled key 8. This key is preferably made of strong rigid plastic, which can be readily molded to the desired shape, and is of a cross sectional size to readily fit into and mate with the hollow portions 9 of the frame members 3. The legs 11 of the key are made slightly smaller than the apertures 9, to readily fit thereinto and provide the main mechanical support between adjacent strips of the frame. The end of each leg 11 is provided with a series of outwardly extending thin relatively flexible fins 12 extending from a reduced section 13 of the leg a distance slightly greater than the cross section of leg 11, and sufiiciently great so that the edges of the fin 12 engage the interior walls of aperture 9 of frame element 3. Thus, as the key is thrust into the aperture, the fins are bent slightly backward as shown in FIG. 4, so that they enter relatively easily, yet it will be apparent that they will offer great resistance to withdrawal. This is due chiefly to the flexibility of the individual fins 12, which tend to straighten out, and thus press against the interior wall of the frame 3 with a force which is greatly in creased whenever any effort is made to pull the key out of place. It will be noted that the main body of the leg 11 provides essentially the rigidity to keep the frame elements in their proper relationship, and also the necessary strength to retain the frame in its proper shape against distorting forces, while the finned end 12 provides a secure action against withdrawal.

FIG. 5 shows a preferred form of the fins, in which they are solid rectangular elements.

FIG. 6 shows a modified form in which diagonal cuts 16 are made in the fins of FIG. 5, which provides more flexibility, and greater ease of insertion.

FIG. 7 shows the fins 12" cut down to, in essence, rectangular tabs, which have still less holding power and still greater flexibility, and which may be preferable in some sizes and weights of framing.

FIG. 8 shows a frame element 3 similar to that shown in FIG. 1, except that the hollow interior is round instead of square or rectangular, which may be easier to fabricate with some materials.

FIG. 9 shows the cross-section of a key adapted for use with FIG. 8.

FIGS. 10-12 show a modified form of the invention as applied to a common type of extruded metal framing 15, shown in this instance as a window frame member having an inner channel for reception of a window pane 16, and formed with an outer channel 17 having inwardly protruding ridges 18, the outer channel 17 being otherwise open at the outer edge of the assembled frame. In this construction, key 19 may be made as before, except that instead of barbs on its outer side, which would have nothing to bear against, even greater strength and rigidity is provided by extending the outer side of one or both legs as shown at 21, and providing two grooves 22 in the sides of the key leg, for reception of the raised ridges 18 of the framing member. This construction may be applied to both legs of the key or only to one leg, the other leg being made more or less flush with the outer edge of the frame as shown in FIG. 13. The end section 21 thus serves to form the locking channels 22, which strengthen the entire structure, help to more positively position the barbs 23, and also provide a bearing or buffer surface on their outer side which serves to protect the frame against scratching and to provide a better bearing surface for sliding the frame in the usual grooves of the casement member in which it is retained.

It will be apparent that the embodiments shown are only exemplary and that various modifications can be made in construction and arrangement within the scope of my invention as defined in the appended claims.

I claim:

1. A rectangular frame comprising separate frame members rectangularly joined at the corners to form a frame, said frame members having axially extending apertures at the ends thereof, a key member of strong material for joining the ends of each two adjacent frame members, said key member fitting into said apertures, said member having two legs forming a rigid right angle with each other and of a uniform cross-sectional size and shape to fit snugly into said apertures, and a series of thin flexible fins extending transversely from each leg adjacent the free end thereof for a suflicient distance to engage the wall of the respective said apertures with a tight friction fit which flexes said fins, the uniform cross-sectional portion of the legs constituting the major part of the length of said legs from said fins to the junction of the legs and being of sufiicient strength and rigidity to hold said frame members together against normal bending stresses to which the frame is subjected in use, said fins preventing withdrawal of said legs.

2. The invention according to claim 1, the axially projected transverse dimensions of said fins being greater than the corresponding inside aperture dimension of said frame members, whereby in the engaged position of said keys in said apertures the fin members are flexed back from the free ends by the interior walls of the respective frame members.

3. The invention according to claim 2, said apertures being substantially rectangular in cross-section. and said key being made of tough, plastic material, rigid in substantial cross-section, but flexible in thin cross-section.

4. The invention according to claim 1, said axial apertures each having an axial slot on the outward side of the frame member so that the outward side of the frame member constitutes an open channel with inwardly turned ends, said key member having at least one leg with the outward side thereof extending through said open channel and having two channels formed in the respective sides of said leg for slidably receiving said inwardly turned ends of the frame channel.

References Cited in the file of this patent UNITED STATES PATENTS 1,817,775 Sipe Aug. 4, 1931 2,101,349 Sharp Dec. 7, 1937 2,587,471 Hess Feb. 26, 1952 2,872,713 Haas Feb. 10, 1959 

